System of electrical distribution



(No Model.)

0.. P. STEINMBTZ. SYSTEM OF ELECTRICAL DISTRIBUTION. No. 533,245.

Patented Ja411.29, 1895.

WI TN ESEEE- mam! (L/{blcl-frv UNTTED STATES PATENT OEErcE.

CHARLES P. STEINMETZ, OF SOHENECTADY, NElV YORK, ASSIGNOR TO THE- GENERAL ELECTRIC COMPANY, OF NEIV YORK.

SYSTEM OF ELECTRICAL DISTRIBUTION.

SPECIFICATION forming part of Letters Patent No. 533,245, dated January 29,1895.

Applicati n fil April 18,1894. Serial No. 507,885. (No model.)

To all whom it may concern: shunt circuit. The armature of the generator Be it known that 1, CHARLES P. STEINMETZ, G, has a main winding W, similar to that ema subject of the Emperor of Germany, residployed in ordinary single-phase alternating ing at Schenectady, county of Schenectady, generators, and a supplementary or phase 55 5 State of New York, have invented a certain modifying coil W, having one terminal connew and useful Improvement in Systems of nected to a central point d in the main wind- Electric Distribution, of which the following ing. The free terminals of the main and supis a specification. plementary coils are connected through col- My present invention relates toa system of lector rings and brushes R, R, R with three 60 1o electrical distribution for multiphase curmains a, b, c. The main and supplementary rents, by which currents sixty degrees apart windings are so proportioned that an electroin phase may be converted into currents one motive force is maintained between the mains hundred and twenty degrees apart in phase, 17, c, and a, Z), sixty degrees apart in phase. or the reverse. This renders possible the Forconvertingtheircurrentsintothree-phase r5 generation and distribution of currents sixty currents, two transformers, T, T, are emdegrees apart in phase, and their conversion ployed, whose primary coils are joined in seinto currents differing by one hundred and ries at the point 6. Their free terminals are twenty degrees in phase which are suitable connected to two of the mains a, c, and their for operating three-phase motors of the ordiconnected terminals at the point eare joined 2o nary type, or other three-phase translating to the third main b. The secondary winddevices. It is also equally possible, as will be in gs of the transformers are coupled in a simiexplained hereinafter, to convert monocyclic lar manner to mains a, b, but one of the currents into three-phase currents. Hence secondary coils as, for example, that of transbythepresentinventi0n,monocyclic currents former T, is reversed, as shown in the dia- 7 2 5 difieringbysixtydegrees andtruethree-phase gram. This will result in shifting the eleccurrents become readily convertible the one tro-motive force maintained between the midinto the other. Suchasystem and the means dle main 1) and one of the outside mains broadly. The conversion of one system into degrees, so thatthe phasal relation of the elec- 8o 0 the other is effected by two transformers in tro-motive forces on the secondary side of the which the primary and secondary windings transformers will be one hundred and twenty occupy relativelya reversed relation,so thatin degrees apart instead of sixty degrees apart, a sixty-degree system the phase of one of the as they are on the primary side. currents will be changed through an angle of The transformers maybe given any desired 8 5 5 one hundred and eighty degrees, thus occuratio of transformation, so that the potential 3' pying a phasal relation with reference to the of the secondary currents will be changed as other two currents such that all three are one well as their phase relation. Instead of rehundred and twenty degrees apart. versing one of the secondary coils, the same In the accompanying drawings, Figure 1 change of phase may be secured by revers- 9o represents in diagram a system of distribuing one of the primary coils. The secondary tion in which monocyclic currents are conthree-phase currents may be used for operat- Verted into three-phase currents, and Fig. 2 ing translating devices of any desired kind represents in a similar manner a system of and coupled in any desired manner, as, for distribution in which three-phase currents are example, lamps, or three-phase motors. 5 converted into monocyclic currents. In the diagram a motor M is shown whose In Fig. 1, G represents what I term a monothree coils are connected at corresponding tercyclic generatorprovided withafield-exciting minals to a common joint g, and whose free coil F, in circuit with a continuous current exterminals are coupled, respectively, to the citer E, which may be either shunt or series mains a, b, c. Any other form of three- I00 wound. In the diagram it is shown asshunt phase motor may be substituted for that wound,andis regulated bya resistanceB in the shown in the diagram. Other translating dcfor effecting this conversioml intend to claim through an angle of one hundred and eighty j vices also may be grouped on the mains a, b, c, in any ordinary manner.

In Fig. 2 the generator G is of the threephase type, and the electro-motive forces 5 maintained between the mains a, Z), c are one hundred and twenty degrees apart in phase. These currents may be converted into a monocyclic system by two transformers, T T connected in series to the mains a, b, c, in a manner similar to the transformers T, T, shown in Fig. Land already described. The secondaries of the transformers are connected to mains a, b, c,but the secondary of transformer T is reversed, so that the two electromotive forces between the main and the mains a, h are sixty degrees apart in phase, instead of one hundred and twenty degrees, as is the case on the primary side. The secondary currents may be utilized for operating translating devices in any desired manner. Motors may be run from all three mains by using a system of transformers, T T in all respects similar to T,T', as described in connection with Fig. 1, or, by modifying somewhat the construction of the ordinary three phase motor, they may be connected directly with the mains a, b, c. This modification consists in reversing one of the coils of the motor, as shown at M. Here the motor has 0 three windings; having one set of terminals connected to a common joint g, and their free terminals to the mains, but instead of the arrangement shown at M, one of the coils, namely f, is reversed. I do not, however, 5 claim this construction in the present appli cation, but merelyillustrate it to explain how motors of this type can be operated from the mains a,b', c,without re'converting the sixtydegree currents which are supposed to flow 40 therein into true three-phase currents.

'What I claim, and desire to secure by Letters Patent of the United States, is

1. The method of electrical distribution herein described, which consists in generating three polyphase currents substantially sixty degrees apart in phase, converting such currents into three currents differing in phase by substantially one hundred and twenty degrees, and utilizing such last named currents for operating translating devices of the ordinary three-phase type, as described.

2. The method herein set forth, which consists in generating electro-motive forces substantially sixty degrees apartin phase, shifting the phase relation of one of the electromotive forces through an angle of one hundred and eighty degrees and thereby changingiit from a sixty-degree relation to the other electro-motivc forces to a one-hundred-andtwenty-degree relation or the reverse, as described.

8. The combination of a three-main interconnected polyphase circuit, with means for maintaining between such mains electro-motive forces substantially sixty degrees apart in phase, with a transformer connected on one side to said mains, and on the other side to a corresponding set of mains, and means for changing the phase relation of the transformed currents from sixty degrees to one hundred and twenty degrees, or vice versa, as described.

4. The combination of a source of polyphase currents sixty degrees apart in phase, with a combined transformer and phase converter reducing the potential of the currents, and converting them into currents one hundred and twenty degrees apart in phase, as described, and motors or other translatii'ig devices of the ordinary three-phase type operated by such transformed currents.

5. The combination in a system of distribution, of a generator of the alternating-current type provided with a phasemodifying coil, and maintaining in a three-main interconnected circuit electro-motive forces sixty degrees apart in phase, with an interconnected system of transformers, as described, transforming and converting the phase relation of the currents from sixty degrees into one hundred and twenty degrees, as described.

6. The combination in a polyphase distribution system, of two transformers having their respective primary and secondary windings coupled in series and arranged in inverse relation to one another, as described, with circuit connections joining the free and connected terminals of the transformers, respectively, with themains of a polyphase distribution system.

7. The combination of an interconnected system of transformers coupled in series and having the primary or secondary winding of one of the transformers reversed, as described, with circuit connections to the mains of a polyphase distribution system, whereby the phase relations of the transformed currents are altered, as set forth.

In witness whereof I have hereunto set my hand this 10th day of April, 189%.

CHARLES P. STEINMETZ. lVitnesses:

B. .1IULL, GENEVEIVE Harms.

ICO 

